JP2019075396A - Stationary induction system - Google Patents

Abstract

To provide a high-reliable and low cost stationary induction system.SOLUTION: The stationary induction system comprises: a stationary induction unit having a winding 11 coated with an electrical insulator; a tank 10 including the stationary induction unit; an insulating coolant 5 filed in the tank 10 for cooling the stationary induction unit; a radiator 12 disposed outside of the tank 10 for cooling the insulating coolant 5; and a piping 13 connecting the radiator 12 and the tank 10 therebetween. The piping 13 has a straight portion 14, and a flow pass of the insulating coolant 5 in the straight portion 14 includes: a coated electrode channel 101 formed of an electrode coated with the same electrical insulator as the winding 11; and a metal electrode 201 formed of a metal. The metal electrode 201 is positioned at the downstream side than the coated electrode channel 101.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a stationary induction battery, and more particularly to a stationary induction battery system capable of detecting charging characteristic fluctuation with high sensitivity.

  In stationary induction devices such as transformers and reactors, devices with high loss density often use a pump to send an insulating refrigerant into the electric device body to cool the electric device body. For example, in a relatively large capacity transformer for transmission systems, insulating oil is circulated by a pump between the transformer body and the cooler to cool the appliance. It is known that the flow of the insulating oil causes charging with the insulator in the transformer, and the progress of charging causes a risk on insulation reliability leading to discharge. This electrification is called fluid electrification, and the characteristics such as the electrification amount of electrification of electrification of electrification of electrification of electrification and electrification charge polarity in transformer change with insulation oil, insulating paper and aging of aging paper and press board, trace additive, and it is difficult to predict By directly measuring the properties of the container's insulating oil, it diagnoses the risk of fluid electrification. Specifically, (a) Insulating oil is collected from the actual device to measure the charging characteristics, and (b) Since the insulating oil passing through the transformer body of the actual device is charged, after the transformer body has passed A device for measuring the charging potential of the insulating oil is provided to measure the change in charging characteristics of the transformer as an individual. (Iii) An insulator-coated electrode is disposed in the insulating oil flow path of the actual device, and a coated electrode The amount of electric charge accumulated on the surface of the coated electrode from the potential and leakage current of the (i) (iii) Insulating oil that has passed through the coated electrode is charged in the opposite polarity to the charged polarity of the coated electrode. There is a method of evaluating the charge amount by providing a device for measuring the ground current from the insulating oil. (A) is a periodic diagnosis accompanied by transformer shutdown, and (B) (C) can be constantly monitored in the operating state.

  In recent years, on-line monitoring based on a method such as (b) (c) (c) has been required to reduce the labor of monitoring work and to be one of the guiding principles of an economical equipment renewal plan. Both have the problem that the SN ratio of the signal to be measured for monitoring is small. There are the following issues with regard to (b) and (c).

  In (b), the charge potential of the insulating oil after passing through the transformer main body is not only the characteristics of the insulating oil but also the configuration of the transformer flow path and the insulating oil flow velocity distribution at each part of the flow path, and the temperature distribution of the transformer and insulating oil Because it depends on such design matters, it is useful for determining whether or not the charging characteristics are normal as the individual transformer. On the other hand, in order to obtain the characteristics of the insulating oil itself, it is necessary to estimate it based on many assumptions, quantitatively predict the charge distribution of the insulator on the transformer flow path, and evaluate the risk to discharge in detail. It is difficult.

  In (iii), there is a method of providing a coated electrode flow path for reference imitating a flow path structure expected to be easily charged in the transformer flow path, and directly predicting the charge state in the flow path structure. However, if the flow channel structure is simulated at the original size of the transformer, there is a problem that the coated electrode flow path becomes large, and if the coated electrode flow path is reduced based on the flow similarity law, the charging characteristics do not follow the similarity law Similarly, there is a problem that quantitative evaluation is difficult as well, and there is a problem in which it is difficult to evaluate the risk when electrification progresses in a channel which is not expected.

  Therefore, for example, in Patent Document 1, the flow in the coated electrode channel can be easily predicted by flowing the insulating oil in the linear coated electrode channel while taking the method of (c) (d). It is possible to correlate the charging characteristics and flow between the electrode and the insulating oil, so that it is possible to constantly evaluate the basic characteristics of the insulating oil for predicting the charged state from the flow distribution inside the transformer body, The charging characteristics can be monitored to quantitatively assess the insulation risk. However, in the method of (d), in general, in the measurement of the charge state of the insulating oil that has passed through the coated electrode, the insulating oil that has passed through the coated electrode is In order to flow into a container at a ground potential (referred to as a relaxation tank) and keep the insulation oil in the relaxation tank for a long time longer than or equal to the electrical time constant of the insulating oil, specifically There is a problem that a large relief tank is required so that the average relief tank stay time divided by the flow rate becomes longer than or equal to the time constant of the insulating oil. The relaxation tank may play a role in electrically insulating the insulating oil and returning it to the transformer flow path (referred to as relaxation). In Patent Document 1, the insulating oil before flowing into the coated electrode is electrically neutralized. A relaxation tank is provided for the purpose.

Japanese Patent Application Laid-Open No. 7-161534

  It is desirable for stationary induction appliances to be able to constantly and quantitatively monitor the risk of insulation reliability with a minimum configuration for economical equipment operation.

The invention described in Patent Document 1 quantitatively evaluates the flow electrification, which is one of the risks on the insulation reliability of a stationary induction appliance, and a part of the piping system of the stationary induction appliance is covered with an insulator. A covered electrode flow path on a straight line composed of the separated electrodes is provided, a relaxation tank for measuring the charge in the insulating refrigerant is provided downstream of the covered electrode flow path, and the stationary induction battery is circulated in the coated electrode flow path to Insulating refrigerant that cools the main body flows, and the electric charge in the insulating refrigerant is absorbed by the coating of the insulator, whereby the insulating refrigerant and the insulator are charged in the reverse polarity, and the charge of the insulating refrigerant charged in the coating electrode flow path By evaluating the amount as the ground current of the relaxation tank for measuring the charge in the insulating refrigerant, it is possible to quantitatively evaluate the charge amount between the insulating refrigerant and the insulator as a value having a correlation with the flow. However, in order to sufficiently observe the charge of the insulating refrigerant flowing into the relaxation tank as the ground current, the time during which the insulating refrigerant stays in the relaxation tank (residence time) is the time constant of the insulating refrigerant (on the order of 10 ³ to 10 ⁵ seconds) Since the residence time is estimated as the relaxation tank volume divided by the flow rate of the insulating refrigerant, a large relaxation tank is required.

  Therefore, it is an object of the present invention to provide a stationary induction appliance system having high insulation reliability and economical efficiency.

  In order to solve the above problems, in a stationary induction appliance system according to the present invention, a stationary induction appliance having a winding coated with an insulator, a tank including the stationary induction appliance, and the tank filled with the tank It has an insulated refrigerant which cools a stationary induction appliance, a cooler which is provided outside the tank and cools the insulated refrigerant, and a pipe which connects the cooler and the tank, and the pipe is a straight portion. The flow path of the insulating refrigerant inside the straight portion is composed of a covered electrode flow path made of an electrode covered with the same insulator as the winding, and a metal electrode flow path made of metal, the metal electrode The flow channel is located downstream of the coated electrode flow channel.

  According to the present invention, the present invention makes it possible to provide a stationary induction appliance system with high insulation reliability and economical efficiency.

The example of a general structure of a stationary induction appliance which applies this invention is shown. The structure of the electrification characteristic detection part of fluid charging and the installation location in Example 1 to which the present invention is applied is shown. The charge transfer path | route in the insulation refrigerant | coolant in the structure of the electrification characteristic detection part of the flow electrical charging of Example 1 to which this invention is applied is shown. The structural example of the electrification characteristic detection installation of the flow electrification in the conventional stationary induction appliance, and the charge transfer course in the insulating refrigerant are shown. 13 shows an example in which a flow straightening passage is provided in the flow passage position port in the charging characteristic detection unit in the first embodiment. The structure which obtains the earthing current of a coating electrode and the earthing current of a metal electrode as a measured value in the charge characteristic detection part in Example 1 is shown. About the application site | part of the stationary induction battery of this invention, FIG. 1 and another example of a form are shown. The structure of the electrification characteristic detection part of fluid charging and the installation location in Example 1 to which the present invention is applied is shown. 17 illustrates an example in which a flow straightening passage is provided in the flow path position port in the charging characteristic detection unit in the second embodiment. The structure which obtains the earthing current of a coating electrode and the earthing current of a metal electrode as a measured value in the charge characteristic detection part in Example 2 is shown.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. The following is merely an example of implementation and is not intended to limit the embodiments of the invention.

  Figure 1 shows the overall structure of the stationary induction appliance. In the stationary induction battery, a stationary induction battery main body provided with a winding 11 formed by winding a conductor coated with an insulating material such as insulating paper in a main body tank 10 is accommodated. The insulating refrigerant 5 is sealed in the main body tank 10, and the stationary induction battery main body is immersed by the insulating refrigerant 5. The winding 11 is provided with a winding cooling flow passage through which the insulating refrigerant 5 flows, and the winding cooling flow passage is connected by a pipe 13 to a cooler 12 provided outside the main tank, and the insulating refrigerant 5 is on the pipe 13 The stationary induction battery body and the cooler 12 are circulated by the provided pump 6. The straight portion 14 is provided on any of the pipes 13.

  Although the configuration of the stationary induction device main body in FIG. 1 shows a configuration in which one winding 11 is provided as the stationary induction device main body in the main body tank 10, the configuration of the stationary induction device main body has a plurality of windings 11; And one or more windings 11 may be wound around an iron core.

The first embodiment will be described with reference to FIGS. 2 to 5. First, FIG. 4 shows a cross-sectional view in the axial direction of the tube as a conceptual diagram in a conventional example of a flow charge measurement mechanism in a stationary induction battery. As shown in FIG. 4, a covered electrode flow path 101 having a flow path formed of a covered electrode 1 covered with the same insulator 1 b as the winding 11 is provided on the pipe 13, and metal is made downstream of the covered electrode flow path 101. Mitigation tank 16 is connected. The coated electrode flow path 101 and the relaxation tank 16 are fixed to the pipe 13 by the insulator flow path 7 formed of an insulator such as a press board and a resin, and the pipe 13 and the coated electrode flow path 101 and the relaxation tank 16 Are electrically isolated by the insulator channel 7. A potential difference detector 3 is provided between the covering electrode 1 and the ground, and a current detector 8 is provided between the relaxation tank 16 and the ground. According to these conventional configurations, for example, when the insulator 1b is insulating paper and the insulating refrigerant 5 is a transformer oil, the negative charge 18 in the insulating refrigerant 5 is adsorbed onto the insulator 1b in the coated electrode flow path 101 The coated electrode 1 is negatively charged, the positive charge 17 remains in the insulating refrigerant 5 and the insulating refrigerant 5 is positively charged, and the positive charge 17 in the insulating refrigerant 5 is an insulating refrigerant because the covered electrode flow path 101 is a straight pipe. When the positive charge 17 is distributed in the laminar boundary layer when the laminar flow 4 is developed or in the developed turbulent flow, it travels like the positive charge transfer path 15 on the slow flow near the coated electrode 1 And move according to the distribution of the flow 4 of the insulating refrigerant (otherwise stirred by meandering and riding the average flow velocity), and flow into the relaxation tank 16, and the positive charge 17 is absorbed by the relaxation tank. 16 is diffused according to the electrical time constant of the insulating refrigerant 5 To move to the ground potential as a ground current through the sum tank 16. Therefore, the potential of the coated electrode 1 and the ground current from the relaxation tank 16 can be measured and monitored during operation of the stationary induction appliance as a characteristic quantity of fluid charging. However, the electrical time constant of the insulating refrigerant 5 is generally large (on the order of 10 ³ to 10 ⁵ seconds), and in order to sufficiently measure the positive charge 17 in the relaxation tank 16 as the ground current, the positive charge 17 in the relaxation tank 16 is The time during which the gas remains is equal to or greater than the electrical time constant of the insulating refrigerant 5, and the time during which the positive charge 17 remains in the relaxation tank 16 is the volume of the relaxation tank 16 divided by the average flow velocity of the insulating refrigerant 5 Therefore, it is necessary to make the mitigation tank 16 larger. Also, in general, the electric potential of the coated electrode 1 and the ground current from the relaxation tank 16 have a small SN ratio, and advanced techniques such as shielding are required.

  The first embodiment is applied to the straight portion 14 on the pipe 13 shown in FIG. FIG. 2 shows a cross section in the tube axis direction of the straight portion 14 to which the present embodiment is applied. As shown in FIG. 2, the straight portion 14 is provided with a straight coated electrode flow path 101 having a flow path formed of the covered electrode 1 covered with the same insulator 1 b as the winding 11. The metal electrode flow path 201 which has formed the flow path is connected by the electrode 2 of the metal or metal oxide which does not have a coating. The coated electrode flow path 101 and the metal electrode flow path 201 are supported in the straight portion 14 by the insulator flow path 7 formed of an insulator such as pressboard or resin, and the straight portion 14 and the coated electrode flow path 101 And the metal electrode channel 201 are electrically insulated by the insulator channel 7. The coated electrode channel 101, the metal electrode channel 201, and the insulator channel 7 have the same channel cross-sectional shape. The flow path of the insulator flow path 7 located upstream of the coated electrode flow path 101 is designed to be equal to or more than the running distance obtained from the flow path cross section and the average flow velocity of the insulating refrigerant 5. A potential difference detector 3 for measuring a potential difference is provided between the coating electrode 1 and the metal electrode 2.

  FIG. 3 shows the charge transfer path in the insulating refrigerant of this embodiment. The negative charge 18 in the insulating refrigerant 5 is adsorbed on the insulator 1b in the covering electrode flow path 101, and the covering electrode 1 is negatively charged, and the positive charge 17 remains in the insulating refrigerant 5 and the insulating refrigerant 5 becomes positive. As the flow 4 of the insulating refrigerant in the coated electrode flow path 101 becomes charged, the positive charge 17 moves on the slow flow near the coated electrode 1 and moves like the positive charge transfer path 15 to be a metal electrode. Since the electric charges 17 reach near the surface 2 and move in the slow flow near the coated electrode 1 even in the metal electrode flow path 201, they are sufficiently adsorbed by the small metal electrode 2 as compared with the conventional relaxation tank 16. Therefore, according to the configuration of the present embodiment, a large structure such as the mitigation tank 16 can be omitted. Further, by measuring the potential difference between the coated electrode 1 and the metal electrode 2, a larger signal can be obtained and the SN ratio can be increased than in the case of measuring the ground potential of one of the electrodes. In other words, in the monitoring equipment of the stationary induction battery for measuring the charge amount of the fluid charge generated between the insulating refrigerant and the insulator in the coating electrode flow path provided in the piping of the stationary induction battery, the coated electrode surface The charged insulating refrigerant located in the vicinity moves to the downstream metal electrode surface following the slow flow of the laminar boundary layer near the surface of the coated electrode and moves to the same laminar boundary layer slow flow near the metal electrode surface. The flow velocity of the laminar boundary layer in the vicinity of the surface of the coated electrode and in the vicinity of the surface of the metal electrode is very slow relative to the average flow velocity of the insulating medium. Since it can be recovered as a ground current, a large structure such as a relaxation tank can be omitted. In addition, by measuring the potential difference between the coated electrode and the metal electrode, it is possible to obtain a larger signal than in the case of measuring the potential of one of the electrodes and to increase the SN ratio.

  In the present embodiment, as shown in FIG. 5, a rectifying grid 9 may be installed at the inlet of the insulator flow path 7 to reduce the influence of the flow from the upstream side of the linear portion 14. Also, instead of measuring the potential difference between the coated electrode 1 and the metal electrode 2, as shown in FIG. 6, the ground current of the coated electrode 1 and the metal electrode 2 is measured, and the signals are added. The charging characteristics may be evaluated. 4 and 6 may be simultaneously configured by switching the measurement circuit with a switch or the like. Although not particularly illustrated, an output device may be provided which displays measurement values, uses a threshold value for the measurement values to indicate visual or auditory warnings, and may have a storage device and computer for collecting and analyzing the measurement values. Further, although the cross section of the coated electrode channel 101, the metal electrode channel 201 and the insulator channel 7 is smaller than that of the straight portion 14 for convenience of explanation, it is desirable that the cross sectional area be large in order to suppress pressure loss. .

  Although the present embodiment shows an example applied to the straight portion 14 on the pipe 13 shown in FIG. 1, a bypass straight portion 14b configured as a bypass flow path of the pipe 13 as shown in FIG. It is also good.

  The cross section in the tube axis direction of the straight portion 14 to which the second embodiment is applied is shown in FIG. The second embodiment is also applied to the straight portion 14 of FIG. 1, and the coated electrode flow passage 101, the metal electrode flow passage 201, and the insulator flow passage 7 are separated from the tube wall of the straight portion 14 with respect to the first embodiment. The coated electrode flow path 101 and the metal electrode flow path 201 are fixed to the straight portion 14 with a support (not shown) or the like via the insulator flow path 7, and the function of the first embodiment is maintained as it is. Since the flow passage cross-sectional area of the straight portion 14 is secured regardless of the flow passage cross-sectional area of the coated electrode flow passage 101, the metal electrode flow passage 201, and the insulator flow passage 7, the pressure loss of the straight portion 14 can be suppressed.

  Also in the second embodiment, as shown in FIG. 9, a rectifying grid 9 may be installed at the inlet of the insulator flow path 7 to reduce the influence of the flow from the upstream side of the straight portion 14. Also, instead of measuring the potential difference between the coated electrode 1 and the metal electrode 2, as shown in FIG. 10, the ground current of the coated electrode 1 and the metal electrode 2 is measured, and the signals are added. The charging characteristics may be evaluated. Although not particularly illustrated, an output device may be provided which displays measurement values, uses a threshold value for the measurement values to indicate visual or auditory warnings, and may have a storage device and computer for collecting and analyzing the measurement values. 8 and 10 may be simultaneously configured by switching the measurement circuit with a switch or the like.

  Although the present embodiment shows an example applied to the straight portion 14 on the pipe 13 shown in FIG. 1, a bypass straight portion 14b configured as a bypass flow path of the pipe 13 as shown in FIG. It is also good.

1: Coating electrode 1b: Insulating material 2: Metal electrode 3: Potentiometric detector 4: Insulating refrigerant flow 5: Insulating refrigerant 6: Pump 7: Insulating flow path 8: Current detector 9: Rectifying grid 10: Main body tank 11: Winding wire 12: Cooler 13: Piping 14: Straight portion 14b: Bypass straight portion 15: Positive charge transfer path 16: Relaxation tank 17: Positive charge 18: Negative charge 101: Coated electrode flow path 201: Metal electrode flow path

Claims (8)

A stationary induction appliance having a winding coated with an insulator;
A tank comprising the stationary induction appliance;
An insulating refrigerant which is filled in the tank and cools the stationary induction battery;
A cooler provided outside the tank for cooling the insulating refrigerant;
Piping connecting the cooler and the tank;
The piping has a straight portion,
The flow path of the insulating refrigerant inside the straight portion is composed of a covered electrode flow path made of an electrode covered with the same insulator as the winding, and a metal electrode flow path made of a metallic material, and the metal electrode flow A stationary induction system, wherein a channel is located downstream of the coated electrode channel. The stationary induction appliance system according to claim 1, wherein
A stationary induction appliance system in which a potential difference detector is connected to the coated electrode channel and the metal electrode channel. The stationary induction appliance system according to claim 1 or 2, wherein
A stationary induction appliance system in which a current detector is connected to the coated electrode channel and the metal electrode channel. The stationary induction appliance system according to any one of claims 1 to 3, wherein
The stationary induction device system having an insulator flow path made of an insulator in the straight portion and the same cross-sectional shape of the coated electrode flow path, the metal electrode flow path, and the insulator flow path. The stationary induction appliance system according to claim 4, wherein
The static induction appliance system according to claim 1, wherein a length of the insulator flow channel located upstream of the coated electrode flow channel is equal to or more than a running distance obtained from a flow channel cross section of the flow channel and an average flow velocity of the insulating refrigerant. The stationary induction appliance system according to claim 5, wherein
A stationary induction appliance system comprising a rectifying grid near the upstream side of the insulator flow path. The stationary induction appliance system according to any one of claims 1 to 6, wherein
The stationary induction appliance system in which the covering electrode channel, the metal electrode channel, and the insulator channel are disposed inwardly away from the outer wall of the straight portion. The stationary induction appliance system according to any one of claims 1 to 7, wherein
A stationary induction appliance system comprising bypass straight parts connected and parallel to the straight parts.

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